1. Field of the Invention
The invention is in the field of caulking guns, and particularly in the field of release mechanisms for caulking guns utilizing either a ratchet-type drive mechanism or a spring biased grip engaging drive mechanism.
2. Description of the Prior Art
Caulking guns widely utilized by both professional homebuilders and the non-professional homeowner. Recently with the emphasis on insulation and energy saving efforts there has been an increasing demand for easy-to-operate caulking guns for use by non-professionals as an aid in reducing fuel bills by proper sealing of windows and doorways. Ratchet-type caulking guns are relatively inexpensive and easy to operate and have thus been widely utilized. The spring biased grip engaging drive type disclosed in U.S. Pat. No. 4,081,112 has also enjoyed an increase in sales. A common disadvantage in the utilization of any caulking gun is the inability to quickly release the pressure on the caulking tube to prevent spillover of the caulking material after a particular bead has been drawn. In some situations, the non-professional user of the caulking gun may even be unaware that the caulking material is needlessly being wasted by failure to timely shut off the flow of caulk by releasing the pressure on the driving piston. One mode of releasing the pressure on the grip engaging plunger mechanism gun is shown in Chang U.S. Pat. No. 4,081,112 issued Mar. 28, 1978. However this means is not automatic and requires the use of two hands, one to hold the gun and the second to actuate the release mechanism.
An improvement limited to the Chang type gun, which is automatic, is disclosed and claimed in Charles Finnegan's application Ser. No. 235,936 filed Feb. 19, 1981 abandoned.
An automatic shut-off for the ratchet type gun is disclosed and claimed in Hodgkins application Ser. No. 248,446 filed on Mar. 27, 1981 abandoned.
It is seen therefore that there is a need for an automatic pressure release mechanism which can be incorporated into either a ratchet-drive caulk gun or a biased grip engaging plunger mechanism gun. Such a gun requires no conscious effort to shut off the flow of caulk.